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Discussion Starter #1
I posted a while ago without having the codes read about not having any throttle response in wet conditions. I've since purchased a Blue Driver code reader and have been playing with it some. The codes were P2139 and P2140. Both are throttle position sensor/switch codes. Any more thoughts on this dilemma? Thanks!
 

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There are three position sensors in the AP. The codes listed indicate that two do not jive with the other.
 

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Discussion Starter #3
Thanks for the response. I went ahead and bought a new pedal assembly and guess what it did it this morning on the way to work. Raining and wet conditions and only does it when I come to a stop never while going down the road. Shut the truck off and restart good to go. Read the codes and got the same ones 2139 and 2140. Are there any sensors in the transmission that could be shorting out and causing this? Getting pretty frustrated to say the least.
 

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The throttle position wires chafe up around the steering column in the cab ..... just start following the wires from the pedal and inspect their condition.

Is it always raining when it does it, or will wet roads cause it to happen also? If it is only when raining, could it be possible that water is leaking through a bad windshield seal into the area behind the dash? When you trace the wires back, look for evidence of moisture. If it will do it under wet road conditions without the rain, then it might be an issue w/ the wiring under the hood.

What year model truck?

btw - is your new pedal assembly OEM or did you buy an aftermarket?
 

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I see from your posts in February that it is an 03. I was asking because I might have some wiring diagrams. Unfortunately I don't for the 03.

https://www.thedieselstop.com/forums/f23/no-throttle-response-654544/

I was also wondering if your PCM still has the cover on it (it covers the top of the drivers battery also).

A bad PCM is a possibility, but not likely IMO ... unless it or a connector is getting wet.

I see the wiring and connector possibilities were brought up in this older thread, so I guess you didn't find any chafes or damaged areas. You may have to do some tests on the wiring, but even that may not help since it is an intermittent issue and seems to only happens when it is wet.
 

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Discussion Starter #6
It has done it without driving the truck. I have started it in the morning and put it in gear and had no throttle after a rainy night. The PCM cover is still on. The pedal assembly was after market. I also put a used OEM from a salvage truck with the same results. I am leaning toward the wire issue myself. Probably dig into tearing the dash apart this weekend. Another guy suggested the GEM module could be bad or getting wet. Any thoughts on that and where is it located? I've read its behind the fuse panel and also its behind the radio. Then I was told my truck didn't even have a GEM module. I really appreciate everyone's feedback. I love the truck but just getting frustrated to the point I'm about to get something else. Not the type of person that likes to sell something with a problem though. Thanks!
 

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This is just FYI information!

Many of the traditional "GEM" computer functions are incorporated in the Instrument Cluster on the 6.0L.

The security module (VSM) is behind the radio.

There is a 4x4 module that Ford calls the GEM.

I doubt that any of these are causing your issues.
 

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Discussion Starter #8
The security module (VSM) you mentioned is interesting. I haven't got a pattern or anything but it beeps at times when I put the truck in gear but not every time. Seems like it should all the time or not at all. I took the plastic off the steering column this weekend and inspected all the wires. I found a small wire that controls the door open beeper unattached from the ignition so I put it back in place but other than that I didn't see any wires worn or anything unusual. It did it again this morning. I still think its transmission related. I can have throttle in neutral then as soon as I put it in gear I have nothing. Any other suggestions? Thanks!
 

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If you think it is your transmission, then you need a code reader that can pull codes from the TCM. The common code readers won't do that. If you download ForScan Lite to a smartphone, it will pull transmission codes. You will need an ELM327 OBDII adapter. Cost is under $40.

Personally I doubt that anything is wrong with your transmission.
 

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Discussion Starter #11
I'm just trying to look at everything. The only reason I think transmission is it only does it when I get off the throttle completely never has it done it when on the throttle. I either come to a stop and it does it or after getting off the throttle to slow down and it does it. Something is telling it to go into limp mode and only in wet conditions and only when not touching the pedal. I really appreciate the help and feedback. Not off in the weeds just looking at all aspects and possibilities. I'm by no means a diesel mechanic that's why I'm looking for help from you guys. Not sure where to go from here though!
Any possibility the FICM could be shorting out in wet conditions? I had it rebuilt and changed out 4 years ago for a different issue. I've changed the crank sensor the ICP valve and had it deleted when I put the second HPOP in. Been pretty pricy truck that's why I really don't want to get rid of it.
 

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Did I miss something? We were discussing a non-responsive accelerator pedal with two AP sensor specific codes right? There are 6 circuits to test which I recommend load testing given the symptoms. If those circuits pass testing you have only two other things that will cause the concern on this truck: the PCM or the pedal assembly.

For get the GEM because you do not have one and forget the VSM - neither would cause this. The transmission is not going to cause this either.

From my experience, concerns like this that are affected by rain for example tend to be harness related. Typically I will find a chafe point and the insulation worn off of a wire and corrosion begins. in these conditions moisture can cause voltage leaks or change the resistance of a connection. You need to access a wiring diagram with connector views.
 

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I see from your posts in February that it is an 03. I was asking because I might have some wiring diagrams. Unfortunately I don't for the 03.

https://www.thedieselstop.com/forums/f23/no-throttle-response-654544/

I was also wondering if your PCM still has the cover on it (it covers the top of the drivers battery also).

A bad PCM is a possibility, but not likely IMO ... unless it or a connector is getting wet.

I see the wiring and connector possibilities were brought up in this older thread, so I guess you didn't find any chafes or damaged areas. You may have to do some tests on the wiring, but even that may not help since it is an intermittent issue and seems to only happens when it is wet.
Sometimes good advice doesn't help if he doesn't have the tools.

mandm - I was hoping that someone else might post up a wiring diagram for you .....

Do some internet searches and you are likely to find some. I will see if I can't get a friend to track one down in the meantime.

I still highly suggest you get a code reader that can read all of the trucks modules. Most cheap ones can't.
 

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Got one sent to me (a tech took time to dig it up for me). See page 9 for a start.

PCM pins 20 (goes to APP pin 10), 25 (goes to APP pin 8), 26 (goes to APP pin 7), 29 (goes to APP pin 5), 37 (goes to APP pin 2) of connector C1381a for the APP wires at the PCM

It is unfortunate that the early advice led you to spend money unnecessarily on a new pedal assembly.

Edit - Page 17 shows the PCM connector C1381a and the wire colors
Also, C1381a is the connector closes to the firewall.
 

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Discussion Starter #15
Thanks so much for the input! Ford doctor I have no idea how to load test circuits so I guess I'm going to have to find someone that does. Like I said I am not a mechanic. I really appreciate your help but like bismic said if I don't have the tools. Bismic I cant open the file for some reason. I'm not very good with computers either. Not sure what to do. What type of code reader do you suggest? The other interesting thing I found with the Blue Driver code reader I have is the absolute throttle position does not read anything. All the other supported data sources read fine. Thanks again guys!
 

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The attached file opens fine for me. I went ahead and deleted it and attached it again though. Please try it again, it should work!

To start with, you could test the resistance in each of the wires I specifically listed above (test from the PCM to the sensor). DVOM set to ohms. I don't like poking holes through wiring (it can lead to corrosion), so you need the proper probe for the PCM plug and the APP plug.

As far as load testing a wire, there are quite a few youtube videos on it. Some people use a headlight bulb for that task. Here is a link to a helpful pdf:
https://support.alldata.com/sites/main/files/file-attachments/electrical_circuit_testing.pdf

The attachment I posted will point out 5 of the 6 wires/circuits mentioned by FDD. IMO if you are not confident of doing a load test, you probably have a pro do it for you.

Hope that helps.
 
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Another thing that may help:


 
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Discussion Starter #18
Thanks for everything! I will keep you posted on what I find. Just one more thing if you don't mind what type of code reader do you recommend?
 

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ForScan Lite (with an ELM327 OBDII adapter) works well and picks up codes that I don't see on ScangaugeII, Torque Pro, SCT, or DashDaq. Also seems to read codes that the Edge CTS doesn't see. Complete package is around $40.
 

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Discussion Starter #20
Hey guys I got the scanner monitor you recommended but not sure what I should be monitoring. I've got the APP 1,2,3 along with some other things but not sure what I'm looking for. I took a screenshot of the truck at idle just not sure how to attach it. The truck is in the shop now for an oil pan change and exhaust leak. He is going to look at some things for the throttle problem. What other things should I be monitoring? Thanks!
 
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